New Delhi, April 4 (IANS): Even though many places across India are experiencing severe to very severe heat waves, two places in Meghalaya received excessive rainfall of more than 300mm in the span of 24 hours, in the last 3-4 days .
But extremely heavy rainfall in both Sohra (Cherrapunji) and Mawsynram is normal during this pre-monsoon period and there have been exceptional days in the past where in some cases rainfall exceeded 400mm in 24 hours .
Indian Department of Meteorology (IMD) records showed Sohra, also known as Cherrapunji, received 190mm of rain in 24 hours till 8:30 a.m. on April 1, 360mm on April 2, barely 2, 6 mm on April 3 and another 150 mm until 8:30 a.m. April 4.
Similarly, a nearby Cherrapunji RKM station recorded 140 mm of rainfall on April 1; 370 mm of rain on April 2; just 4.3 mm on April 3 when Monday’s data was not yet available.
Mawsynram recorded 330mm on April 1, 390mm on April 2, just 2.4mm on April 3 while Monday’s data was unavailable.
The IMD classifies precipitation between 64.5 and 115.5 mm as “heavy rain”; between ‘115.6 and 204.4 mm’ as ‘Very Heavy Rain’, and anything above 204.4 mm as ‘Extremely Heavy Rain’.
Incidentally, most other parts of Meghalaya also received heavy rains, but only these two places received heavy rains. Rainfall recorded till 8:30 am Monday for other places in Meghalaya include: Anlarem – 410mm, Mawjyrwat – 240mm, Jowai – 200mm, Mawphlang – 190mm.
“These places – Mawsynram and Sohra – have a very typical watershed shape and the presence of orographic features. The watershed is funnel-shaped and opens to the south – facing the Bay of Bengal – so every time as moisture-laden southerly winds arrive at lower level, they hit these places at almost 90 degrees and due to orographic elevation, these areas receive increased rainfall,” explained Sunit Das of IMD Guwahati.
IMD records showed that Cherrapunji received up to 644.2 mm of rainfall during the pre-monsoon season on April 16, 1990. Lately it was 420 mm on April 24, 2016 and 330 mm on April 27, 2017.
Under the influence of strong southwesterly winds from the Bay of Bengal to the northeast states at lower tropospheric levels, fairly widespread to widespread rainfall is very likely over Arunachal Pradesh, Assam-Meghalaya over the next five days and isolated to scattered rainfall over Nagaland, Manipur, Mizoram and Tripura for the next two days and reduction thereafter.
Isolated heavy rains are also likely over Arunachal Pradesh on Tuesday and over Assam-Meghalaya on April 5-7-8 and over Sub-Himalayan West Bengal-Sikkim from April 5-7.